


Tunnel Vision

by Reynaert



Category: Fate/Zero, Fate/stay night & Related Fandoms
Genre: Alternate Universe - Canon Divergence, Crest Worms, Dubious Consent, Hate Sex, M/M, Mana Transfer, Oral Sex, Rough Sex, Tragedy
Language: English
Status: Completed
Published: 2021-01-27
Updated: 2021-01-27
Packaged: 2021-03-12 15:21:53
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,244
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29012742
Author URL: https://archiveofourown.org/users/Reynaert/pseuds/Reynaert
Summary: After fighting Kariya and leaving him for dead, Tokiomi pays Zouken a visit. Kariya’s contradictory accusations have made him wary of the old Matou family head, and he needs to confirm his daughter’s safety.
Relationships: Matou Kariya/Tohsaka Tokiomi
Kudos: 3





	Tunnel Vision

**Author's Note:**

> I've rewritten this upload on 16/2/2021. Read the tags please! Something with dead doves that one should not consume.

Tohsaka Tokiomi looks up at the sky, still filled with the magical residue that was left by the monster that Caster had summoned into being. Perhaps tonight is a good night to pay Zouken a visit, since he doesn’t have to worry about running into Berserker anymore now that Kariya is gone. Of course, the man’s baseless accusations against him can’t have been true. It was clearly stated in the contract that he signed with Zouken that Sakura would receive the Matou family crest. They should be giving her the best possible education. Still, Tokiomi wants to confirm her safety. It’s the least he can do to ease the part of his mind that wants to take Kariya seriously, despite knowing better.

For all the mysteries that shroud the logic behind Kariya’s actions, there is one thing that Tokiomi knows for certain and can’t ignore even if he wanted to: Kariya loved Aoi as if she were his own wife and loved Sakura and Rin as if they were his own daughters. He would only want the best for them. Especially for Sakura. She was his favourite, after all. In all honesty, Tokiomi had quietly hoped to encourage Kariya’s return to the Matou family by sending her there. Maybe he would have been able to become a mage worth fighting if he had picked up his education again. But he hadn’t expected this. Those vile insects must have been a shortcut into using the magic circuits Kariya himself had chosen to neglect. That’s quite the opposite of proper training. It did not make any sense.

Then again, Kariya’s behaviour had never made much sense. He had also been the one to reject Aoi’s advances on him back when they had all been younger, despite their obvious feelings for each other. It broke her heart when he suddenly disappeared. But Kariya didn’t even seem to notice that he was treating Aoi and Tokiomi as collateral damage when he distanced himself from the world of magecraft. Aoi had welcomed Kariya back into her life, and Tokiomi didn’t consider it befitting of a gentleman such as himself to dig up past skeletons either. But their friendship had never truly revived itself. Kariya should have known that too.

Tokiomi is grateful for having Aoi as his wife, and he really does love her, but if there is one thing that he hates more than anything, it is being someone’s second choice. Especially if the man he has lost to on the battlefield of romance is someone that he cannot respect as a mage or even as a human being. He tried his best to ignore these feelings of jealousy. To forget all about his weakness and take pride in his family. But the feelings still persisted. And thus, despite the warmth that Kariya brought to the Tohsaka household whenever he visited them, and despite the way his daughters’ eyes lit up whenever their ‘uncle’ appeared, he is glad that he killed that man. He won’t say it out loud, but there’s a sigh of relief on his lips, and the weight in the pit of his stomach finally seems to have lifted.

Upon Tokiomi’s arrival at the Matou family mansion, Sakura is the one to open the door for him and let him in. She refuses to refer to him as her father, and instead insists on calling him ‘Tokiomi-san’. That is to be considered fair given the circumstances. Still, Tokiomi can’t shake the feeling that there’s something off about her appearance. But perhaps she has just gotten taller.

Tokiomi has brought a single white rose with him, to pay his respects for the recently departed, the man he killed earlier that night. They meet Zouken in the living room. The old man’s beady eyes glisten in the light coming from the burning wood in the fireplace.

“Matou Zouken,” Tokiomi says, elegant as ever. “It has been a while. I’m sorry about the loss of your son.”

“You mean Kariya?” Zouken laughs. “Kariya is still alive. You didn’t know?”

Wait, what? No. It can’t be.

“What do you mean?”

Zouken is obviously amused by Tokiomi’s lack of knowledge on the situation. It’s akin to lifting the most exotic fish in the tank out of the water and letting it fall to the floor, just to watch it flair around and struggle to breathe on land. This should become fun.

“Come with me.” Zouken says. “I will show you.”

Zouken walks in front of him, followed by Sakura. They’re taking Tokiomi to an underground chamber below the mansion. The sounds of their footsteps echo against the walls as they descend the stairs. The only other noises in that pit of darkness are the strangled groans of a man in perpetual agony. Tokiomi’s eyes widen.

“Kariya.”

At once, the uneasiness in his stomach returns. His sight having grown accustomed to the darkness, Tokiomi discerns the figure of a man tied to the basement wall with two chains keeping his wrists in place. Kariya is unclothed except for the black pants he wears. His bare chest reveals the parts of his skin that have been burned by Tokiomi’s fire spell against him, exposing the rotten flesh underneath. The unmistakable stench of rust and fungus penetrates the air.

Kariya lifts his face up, looking straight into Tokiomi’s bright blue eyes. He fights against his chains. Tokiomi can’t help but smile at the man’s futile attempts to reach him.

“Tohsaka Tokiomi! You bastard! I will kill you!”

Zouken uses his wooden cane to push Kariya’s back against the stone walls of the chamber, halting his movements.

“Tokiomi. Take his pants off.”

The order comes as a surprise to Tokiomi, but it is clear that the old man is serious. It’s enough to spark his curiosity. He didn’t expect Zouken to be so eager to humiliate his son in front of him, but he can’t complain. This is everything Tokiomi has dreamed of. He had taken pity on Kariya back when they were fighting each other on Fuyuki Bridge, but right now, with his relief shattered by the fact that Kariya is still alive, he wants nothing more than to torture him slowly and watch as the last signs of life leave his pathetic body.

Tokiomi walks up to Kariya and places a hand on the man’s hip. Their faces are only inches apart, and Tokiomi can feel Kariya’s breath on his cheek when he opens the belt and undoes the button. He pulls the zipper of Kariya’s pants down and accidentally makes contact with skin, earning him a gasp. It is then that Tokiomi notices that Kariya isn’t wearing anything underneath.

He turns around.

“I think it is better for Sakura-chan to go back upstairs.”

“The girl will stay,” Zouken replies.

The old man must be aiming to teach Sakura the consequences of behaving irresponsibly. Tokiomi can’t argue with that, and Kariya’s feelings about being stripped naked in front of her shouldn’t be his concern. He turns back towards him and pulls his pants down, freeing his legs from the fabric before tossing it away.

“Please, no…” Kariya whimpers, breathing heavily.

Tokiomi stands up. He looks at Kariya’s erection.

“I didn’t know you felt that way about me,” he smirks. Tokiomi more than welcomes the ego boost.

Zouken laughs again. “It’s not because of you.”

He uses his wooden cane to force Kariya to move his leg.

“Up.”

Kariya does as he is told and lifts up the leg that isn’t paralysed. There is a crest worm sticking out of his ass, writhing against the opening there in an attempt to burrow its way fully inside. Zouken pushes his cane against the worm, forcing it in deep enough so that none of it is left visible anymore. Kariya moans, helplessly. His whole body convulses as the worms inside of him are stirred up into a frenzy, gnawing away at his flesh. Tokiomi is both shocked and turned on at the sight. He can feel himself unexpectedly growing hard in his pants, and he hates Kariya for that. Did he look at him with that kind of attention before? No. It must be because his rival is being treated like an animal.

“I’ll take Sakura back to the living room,” Tokiomi says. He turns around, grabbing Sakura by the hand in order to drag her along, away from there.

“What’s wrong, Tokiomi-san? Uncle Kariya is just spending time with the worms.”

Tokiomi looks at his daughter in confusion.

“She’s used to it,” Zouken says. “This is part of her education as well.”

And then the realization crashes in on Tokiomi, a wave of fire coursing through his veins. This must be the reason for Kariya’s contradictory behaviour. If these creatures are part of their education, then he should have never sent Sakura here. Tokiomi clenches his hand around his staff. The jewel on top shines fiercely.

“Intensive Einäscherung!”

A ball of flames is hurled into Zouken’s direction, but the old man just laughs and melts away into the darkness.

“I’ll present you with an opportunity, Tokiomi. My son won’t last another twelve hours if he isn’t fed with life force to sustain himself. It’s up to you whether you want that to be your mana or Sakura’s.”

Matou Zouken’s voice disappears, leaving Tokiomi and Sakura alone with the lustful groans of the man in front of them. Tokiomi is astonished to notice that Kariya’s erection is still leaking pre-cum. It’s enough to make Tokiomi’s stomach twist in nausea. He picks Sakura up in his arms and makes his way towards the stairs, climbing the steps as fast as he can. When he nears the end of the staircase, Kariya’s voice calls out to him.

“Tokiomi. Take Sakura as far away from here as you can. Please.”

Tokiomi stops walking.

“I can’t,” he says. His voice is filled with regret. “I signed a Geis with Zouken when he adopted her. I’m not her father anymore.”

The words take a moment to process before Kariya screams. There are tears streaming down the man’s face as he struggles against the chains, and an unfamiliar feeling wells up inside of Tokiomi, one that matches the cries of the man in the basement below. For the first time in his life, Tokiomi experiences the agony of self-hatred.

When he reaches the hallway, he tells Sakura to go to her room. Fortunately, she doesn’t question him this time. Tokiomi unbuttons his crimson jacket. His blood races through his veins and his hands are trembling, but at the same time he feels oddly calm. There’s a sense of hyperawareness that enables him to do what he must. He folds the jacket in half and hangs it over the wooden railing. Then he pulls off the blue ribbon around his collar and unbuttons his shirt, taking it out of his pants before turning back to the struggling man in the worm room below. Tokiomi is still half-hard. If Zouken is implying that he plans for Kariya to take Sakura’s virginity, Tokiomi has to do everything in his power to make sure that doesn’t happen.

On the cold, damp floor, Tokiomi notices the white rose. He must have dropped it earlier.

“Tokiomi! I will rip your heart out and feed it to the worms!”

“That’s fine by me.”

Tokiomi is face to face with Kariya again. He rolls up his sleeves and stares into the man’s eyes. Their lips are close enough to touch. Tokiomi cups Kariya’s cheek and kisses him softly. Their tongues entwine, and Kariya can feel the hairs of Tokiomi’s perfectly groomed goatee press against his chin. Then, with the lightest of movements, Tokiomi brushes his thumb against his right nipple. Kariya whines, leaning into the sensation involuntarily, hungry for more. It’s downright humiliating.

“Just fuck me and get it over with, Tokiomi,” Kariya growls.

But the finger on his nipple doesn’t leave its place. Instead, Tokiomi flicks the sensitive bud with his fingernail, pinching it and rubbing it between his index finger and thumb. The worms underneath of Kariya’s skin react to the touch and crawl around restlessly. They are just as mana starved as he is. Tokiomi moves his hand lower, brushing the skin on Kariya’s waist lightly before moving all the way down to his dick, his balls, and travelling even further beyond that. Finally, his fingers rest on Kariya’s taint. Tokiomi pushes against it, and Kariya moans.

“Ah!”

“Why didn’t you tell us about this?” Tokiomi asks. The anger in his voice is unmistakable.

“Wasn’t it clear?” Kariya groans back. “I couldn’t have been more obvious.”

“That’s no excuse.”

Tokiomi looks at him, his blue eyes burning like a fire in the darkness of the room.

“You know how family secrets work,” Kariya replies. “Zouken made sure I couldn’t go into detail. He would have killed me.”

Kariya can hear a zipper being pulled down, followed by fabric. Tokiomi grabs his legs and lifts them up, slamming him hard against the wall. Kariya shouts out in pain. The head of Tokiomi’s penis pushes against his sphincter muscle. It’s slick from the blood that the crest worms have left behind. Tokiomi brings his lips to Kariya’s ear.

“Then you should have died,” he hisses.

He pushes in slowly to penetrate him, feeling his dick be taken in one inch at a time. Tokiomi licks at Kariya’s ear before sinking his teeth into the skin. Kariya groans. He bites down on Tokiomi’s shoulder as what’s inside of him grows harder. It’s too good. Kariya has been craving cock for a while now, and he hates to admit that Tokiomi’s shape is exactly right, filling him up and forcing his attention away from the agony of being eaten alive, even if he knows that it’s just temporary.

“I’m already dead,” Kariya struggles out in between ragged breaths.

Tokiomi pulls and pushes his dick out and back into the man, fucking Kariya roughly and speeding up his tempo. It doesn’t take another second before Kariya starts to shamelessly ride him, like a dog in heat, chasing his release from the agitation of the worms around his organs and along his spine. There’s a steady rhythm in Tokiomi’s thrusts, but Kariya doesn’t even care to ride him in synch with it. He wishes that his arms weren’t tied to the wall behind him. He wants to sink his nails into Tokiomi, into the man that he hates enough to make his blood boil. Kariya wrestles against the chains, but they don’t give in.

“I’m sorry,” Tokiomi whispers. A tear runs down his cheek, followed by another. Kariya looks at Tokiomi in surprise, but quickly closes his eyes again when Tokiomi starts pushing into him harder, finding a pace violent enough to make Kariya cry out. Cum oozes out of Kariya’s dick and his anus spasms, milking Tokiomi while he keeps slamming into his ass.

“Ah... Yes!”

The crest worms against Kariya’s prostate are writhing, and force him into a continued state of orgasm. They feed on his ecstasy. It’s driving him mad. Tokiomi bites his neck and shoots his semen inside of Kariya. The sudden boost in life force makes Kariya’s head spin and his neck hairs stand on end. He feels wide awake again.

Tokiomi rides out his orgasm. He sucks the skin of Kariya’s neck to leave his mark. They’re both breathing heavily, and Kariya is quivering when Tokiomi finally pulls out.

“Ah, more,” he whines.

Tokiomi looks at him. He wishes he could give Kariya what he wants, but it will probably take a while for him to get hard again. Hesitantly, Tokiomi kneels down, his face now at the same level as Kariya’s cock. There’s cum oozing out of it still, the mana being wasted. Tokiomi laps up the cum with his tongue. It tastes horrible, but that is to be expected.

With his free hand, Tokiomi heals the damaged patches of skin on Kariya’s torso. He hears him groan, bucking against Tokiomi’s mouth until his dick is inside of it. It has been a while since Tokiomi has last felt his lips close around another man’s erection. He hasn’t sought out any such encounters since his marriage. Tokiomi wonders if he should tell Aoi about this. He can’t bring himself to imagine her reaction. Not only has he fucked the man she once loved, but now he is also giving him fellatio.

Kariya can’t think anymore. His braincells can only focus on getting off, on wanting more of that sweet release. He thrusts his hips forward in a frenzy, fucking Tokiomi’s face. Out of all things, he never expected the powerful and proud magus to give him head with the same lips that have kissed Aoi. Tokiomi’s tongue presses against him in all the right ways, and Kariya can feel his balls tighten again. God be damned if this is just another worm-induced wet dream.

Just when Tokiomi notices the traces of another person’s healing magic on Kariya’s internal organs, he feels a burst of salty fluid coming out of the spasming dick in his mouth. Kariya moans breathlessly, his throat sore and painful. Tokiomi makes sure not to spill a single drop. He gets up and grabs Kariya’s jaw, forcing his mouth open. With his fingers, Tokiomi grabs ahold of Kariya’s tongue, pulling it out. He gathers the cum in his mouth and spits it onto Kariya’s tongue and down his throat.

“This belongs to you,” he says. “Make sure you survive.”

He wipes his mouth and then zips his pants back up, tucking his shirt in.

“I’ll find a way to get both you and Sakura out of this place when I get to the Root.”

Kariya swallows his cum and laughs, cynically. “That would be nice.”

Tokiomi hesitates for a second.

“I mean it,” he says.

He bends down to help Kariya put on his own pants, guiding his legs into the fabric and pulling it up. He secures the pants around his waist with the belt, and Kariya is glad that he isn’t looking directly at him. He doesn’t want Tokiomi to see him blush. There’s a moment of awkward silence between them. Then Tokiomi cups Kariya’s cheek, healing the burn wounds there. Their lips meet, and Tokiomi squeezes Kariya’s ass through the fabric of his pants. Their bodies press against each other, still intimately familiar and unconcerned with the hostility that usually exists between them.

Tokiomi’s attention is caught by those traces of another person’s healing magic again. They’re strangely familiar.

“Did Zouken heal you?”

“That vampire? No.” Kariya answers. “A father from the church dragged me back here.”

Kotomine Kirei? Tokiomi will need to have a word with the apprentice first thing tomorrow morning.

“Hmm. Focus your attention on defeating Saber from now on,” he says to Kariya.

“How do I know that you will keep your word?”

Tokiomi picks up the white rose from the damp floor of the room and tucks it behind Kariya’s ear.

“You don’t.”

It’s the last exchange between them before Tokiomi leaves, and Kariya is left wondering if he really plans on saving the both of them. Is that even possible at this point? He can feel Tokiomi’s cum escape from his ass, running down his leg in small rivulets. Kariya tries his best to clench the muscle and keep it inside. It’s too soon to give up, and still too early to die.

**Author's Note:**

> GILGAMESH: Tokiomi, use your Flamethrower!  
> LANCELOT: Kariya, Harden! Use String Shot!


End file.
